diff --git a/.ci_support/environment.yml b/.ci_support/environment.yml
index 2e65587..636aa96 100644
--- a/.ci_support/environment.yml
+++ b/.ci_support/environment.yml
@@ -5,7 +5,7 @@ dependencies:
   - coverage
   - codacy-coverage
   - lammps >=2020.12.24
-  - mpi4py >=3.0.3
+  - mpi4py =3.0.3
   - openmpi
   - numpy
   - distributed